block/blk-mq-debugfs.c

   1 /*
   2  * Copyright (C) 2017 Facebook
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <https://www.gnu.org/licenses/>.
  15  */
  16
  17 #include <linux/kernel.h>
  18 #include <linux/blkdev.h>
  19 #include <linux/debugfs.h>
  20
  21 #include <linux/blk-mq.h>
  22 #include "blk.h"
  23 #include "blk-mq.h"
  24 #include "blk-mq-debugfs.h"
  25 #include "blk-mq-tag.h"
  26
  27 static int blk_flags_show(struct seq_file *m, const unsigned long flags,
  28                           const char *const *flag_name, int flag_name_count)
  29 {
  30         bool sep = false;
  31         int i;
  32
  33         for (i = 0; i < sizeof(flags) * BITS_PER_BYTE; i++) {
  34                 if (!(flags & BIT(i)))
  35                         continue;
  36                 if (sep)
  37                         seq_puts(m, "|");
  38                 sep = true;
  39                 if (i < flag_name_count && flag_name[i])
  40                         seq_puts(m, flag_name[i]);
  41                 else
  42                         seq_printf(m, "%d", i);
  43         }
  44         return 0;
  45 }
  46
  47 #define QUEUE_FLAG_NAME(name) [QUEUE_FLAG_##name] = #name
  48 static const char *const blk_queue_flag_name[] = {
  49         QUEUE_FLAG_NAME(QUEUED),
  50         QUEUE_FLAG_NAME(STOPPED),
  51         QUEUE_FLAG_NAME(DYING),
  52         QUEUE_FLAG_NAME(BYPASS),
  53         QUEUE_FLAG_NAME(BIDI),
  54         QUEUE_FLAG_NAME(NOMERGES),
  55         QUEUE_FLAG_NAME(SAME_COMP),
  56         QUEUE_FLAG_NAME(FAIL_IO),
  57         QUEUE_FLAG_NAME(NONROT),
  58         QUEUE_FLAG_NAME(IO_STAT),
  59         QUEUE_FLAG_NAME(DISCARD),
  60         QUEUE_FLAG_NAME(NOXMERGES),
  61         QUEUE_FLAG_NAME(ADD_RANDOM),
  62         QUEUE_FLAG_NAME(SECERASE),
  63         QUEUE_FLAG_NAME(SAME_FORCE),
  64         QUEUE_FLAG_NAME(DEAD),
  65         QUEUE_FLAG_NAME(INIT_DONE),
  66         QUEUE_FLAG_NAME(NO_SG_MERGE),
  67         QUEUE_FLAG_NAME(POLL),
  68         QUEUE_FLAG_NAME(WC),
  69         QUEUE_FLAG_NAME(FUA),
  70         QUEUE_FLAG_NAME(FLUSH_NQ),
  71         QUEUE_FLAG_NAME(DAX),
  72         QUEUE_FLAG_NAME(STATS),
  73         QUEUE_FLAG_NAME(POLL_STATS),
  74         QUEUE_FLAG_NAME(REGISTERED),
  75         QUEUE_FLAG_NAME(SCSI_PASSTHROUGH),
  76         QUEUE_FLAG_NAME(QUIESCED),
  77         QUEUE_FLAG_NAME(PREEMPT_ONLY),
  78 };
  79 #undef QUEUE_FLAG_NAME
  80
  81 static int queue_state_show(void *data, struct seq_file *m)
  82 {
  83         struct request_queue *q = data;
  84
  85         blk_flags_show(m, q->queue_flags, blk_queue_flag_name,
  86                        ARRAY_SIZE(blk_queue_flag_name));
  87         seq_puts(m, "\n");
  88         return 0;
  89 }
  90
  91 static ssize_t queue_state_write(void *data, const char __user *buf,
  92                                  size_t count, loff_t *ppos)
  93 {
  94         struct request_queue *q = data;
  95         char opbuf[16] = { }, *op;
  96
  97         /*
  98          * The "state" attribute is removed after blk_cleanup_queue() has called
  99          * blk_mq_free_queue(). Return if QUEUE_FLAG_DEAD has been set to avoid
 100          * triggering a use-after-free.
 101          */
 102         if (blk_queue_dead(q))
 103                 return -ENOENT;
 104
 105         if (count >= sizeof(opbuf)) {
 106                 pr_err("%s: operation too long\n", __func__);
 107                 goto inval;
 108         }
 109
 110         if (copy_from_user(opbuf, buf, count))
 111                 return -EFAULT;
 112         op = strstrip(opbuf);
 113         if (strcmp(op, "run") == 0) {
 114                 blk_mq_run_hw_queues(q, true);
 115         } else if (strcmp(op, "start") == 0) {
 116                 blk_mq_start_stopped_hw_queues(q, true);
 117         } else if (strcmp(op, "kick") == 0) {
 118                 blk_mq_kick_requeue_list(q);
 119         } else {
 120                 pr_err("%s: unsupported operation '%s'\n", __func__, op);
 121 inval:
 122                 pr_err("%s: use 'run', 'start' or 'kick'\n", __func__);
 123                 return -EINVAL;
 124         }
 125         return count;
 126 }
 127
 128 static void print_stat(struct seq_file *m, struct blk_rq_stat *stat)
 129 {
 130         if (stat->nr_samples) {
 131                 seq_printf(m, "samples=%d, mean=%lld, min=%llu, max=%llu",
 132                            stat->nr_samples, stat->mean, stat->min, stat->max);
 133         } else {
 134                 seq_puts(m, "samples=0");
 135         }
 136 }
 137
 138 static int queue_write_hint_show(void *data, struct seq_file *m)
 139 {
 140         struct request_queue *q = data;
 141         int i;
 142
 143         for (i = 0; i < BLK_MAX_WRITE_HINTS; i++)
 144                 seq_printf(m, "hint%d: %llu\n", i, q->write_hints[i]);
 145
 146         return 0;
 147 }
 148
 149 static ssize_t queue_write_hint_store(void *data, const char __user *buf,
 150                                       size_t count, loff_t *ppos)
 151 {
 152         struct request_queue *q = data;
 153         int i;
 154
 155         for (i = 0; i < BLK_MAX_WRITE_HINTS; i++)
 156                 q->write_hints[i] = 0;
 157
 158         return count;
 159 }
 160
 161 static int queue_poll_stat_show(void *data, struct seq_file *m)
 162 {
 163         struct request_queue *q = data;
 164         int bucket;
 165
 166         for (bucket = 0; bucket < BLK_MQ_POLL_STATS_BKTS/2; bucket++) {
 167                 seq_printf(m, "read  (%d Bytes): ", 1 << (9+bucket));
 168                 print_stat(m, &q->poll_stat[2*bucket]);
 169                 seq_puts(m, "\n");
 170
 171                 seq_printf(m, "write (%d Bytes): ",  1 << (9+bucket));
 172                 print_stat(m, &q->poll_stat[2*bucket+1]);
 173                 seq_puts(m, "\n");
 174         }
 175         return 0;
 176 }
 177
 178 #define HCTX_STATE_NAME(name) [BLK_MQ_S_##name] = #name
 179 static const char *const hctx_state_name[] = {
 180         HCTX_STATE_NAME(STOPPED),
 181         HCTX_STATE_NAME(TAG_ACTIVE),
 182         HCTX_STATE_NAME(SCHED_RESTART),
 183         HCTX_STATE_NAME(START_ON_RUN),
 184 };
 185 #undef HCTX_STATE_NAME
 186
 187 static int hctx_state_show(void *data, struct seq_file *m)
 188 {
 189         struct blk_mq_hw_ctx *hctx = data;
 190
 191         blk_flags_show(m, hctx->state, hctx_state_name,
 192                        ARRAY_SIZE(hctx_state_name));
 193         seq_puts(m, "\n");
 194         return 0;
 195 }
 196
 197 #define BLK_TAG_ALLOC_NAME(name) [BLK_TAG_ALLOC_##name] = #name
 198 static const char *const alloc_policy_name[] = {
 199         BLK_TAG_ALLOC_NAME(FIFO),
 200         BLK_TAG_ALLOC_NAME(RR),
 201 };
 202 #undef BLK_TAG_ALLOC_NAME
 203
 204 #define HCTX_FLAG_NAME(name) [ilog2(BLK_MQ_F_##name)] = #name
 205 static const char *const hctx_flag_name[] = {
 206         HCTX_FLAG_NAME(SHOULD_MERGE),
 207         HCTX_FLAG_NAME(TAG_SHARED),
 208         HCTX_FLAG_NAME(SG_MERGE),
 209         HCTX_FLAG_NAME(BLOCKING),
 210         HCTX_FLAG_NAME(NO_SCHED),
 211 };
 212 #undef HCTX_FLAG_NAME
 213
 214 static int hctx_flags_show(void *data, struct seq_file *m)
 215 {
 216         struct blk_mq_hw_ctx *hctx = data;
 217         const int alloc_policy = BLK_MQ_FLAG_TO_ALLOC_POLICY(hctx->flags);
 218
 219         seq_puts(m, "alloc_policy=");
 220         if (alloc_policy < ARRAY_SIZE(alloc_policy_name) &&
 221             alloc_policy_name[alloc_policy])
 222                 seq_puts(m, alloc_policy_name[alloc_policy]);
 223         else
 224                 seq_printf(m, "%d", alloc_policy);
 225         seq_puts(m, " ");
 226         blk_flags_show(m,
 227                        hctx->flags ^ BLK_ALLOC_POLICY_TO_MQ_FLAG(alloc_policy),
 228                        hctx_flag_name, ARRAY_SIZE(hctx_flag_name));
 229         seq_puts(m, "\n");
 230         return 0;
 231 }
 232
 233 #define REQ_OP_NAME(name) [REQ_OP_##name] = #name
 234 static const char *const op_name[] = {
 235         REQ_OP_NAME(READ),
 236         REQ_OP_NAME(WRITE),
 237         REQ_OP_NAME(FLUSH),
 238         REQ_OP_NAME(DISCARD),
 239         REQ_OP_NAME(ZONE_REPORT),
 240         REQ_OP_NAME(SECURE_ERASE),
 241         REQ_OP_NAME(ZONE_RESET),
 242         REQ_OP_NAME(WRITE_SAME),
 243         REQ_OP_NAME(WRITE_ZEROES),
 244         REQ_OP_NAME(SCSI_IN),
 245         REQ_OP_NAME(SCSI_OUT),
 246         REQ_OP_NAME(DRV_IN),
 247         REQ_OP_NAME(DRV_OUT),
 248 };
 249 #undef REQ_OP_NAME
 250
 251 #define CMD_FLAG_NAME(name) [__REQ_##name] = #name
 252 static const char *const cmd_flag_name[] = {
 253         CMD_FLAG_NAME(FAILFAST_DEV),
 254         CMD_FLAG_NAME(FAILFAST_TRANSPORT),
 255         CMD_FLAG_NAME(FAILFAST_DRIVER),
 256         CMD_FLAG_NAME(SYNC),
 257         CMD_FLAG_NAME(META),
 258         CMD_FLAG_NAME(PRIO),
 259         CMD_FLAG_NAME(NOMERGE),
 260         CMD_FLAG_NAME(IDLE),
 261         CMD_FLAG_NAME(INTEGRITY),
 262         CMD_FLAG_NAME(FUA),
 263         CMD_FLAG_NAME(PREFLUSH),
 264         CMD_FLAG_NAME(RAHEAD),
 265         CMD_FLAG_NAME(BACKGROUND),
 266         CMD_FLAG_NAME(NOUNMAP),
 267         CMD_FLAG_NAME(NOWAIT),
 268 };
 269 #undef CMD_FLAG_NAME
 270
 271 #define RQF_NAME(name) [ilog2((__force u32)RQF_##name)] = #name
 272 static const char *const rqf_name[] = {
 273         RQF_NAME(SORTED),
 274         RQF_NAME(QUEUED),
 275         RQF_NAME(SOFTBARRIER),
 276         RQF_NAME(FLUSH_SEQ),
 277         RQF_NAME(MIXED_MERGE),
 278         RQF_NAME(MQ_INFLIGHT),
 279         RQF_NAME(DONTPREP),
 280         RQF_NAME(PREEMPT),
 281         RQF_NAME(COPY_USER),
 282         RQF_NAME(FAILED),
 283         RQF_NAME(QUIET),
 284         RQF_NAME(ELVPRIV),
 285         RQF_NAME(IO_STAT),
 286         RQF_NAME(ALLOCED),
 287         RQF_NAME(PM),
 288         RQF_NAME(HASHED),
 289         RQF_NAME(STATS),
 290         RQF_NAME(SPECIAL_PAYLOAD),
 291 };
 292 #undef RQF_NAME
 293
 294 #define RQAF_NAME(name) [REQ_ATOM_##name] = #name
 295 static const char *const rqaf_name[] = {
 296         RQAF_NAME(COMPLETE),
 297         RQAF_NAME(POLL_SLEPT),
 298 };
 299 #undef RQAF_NAME
 300
 301 int __blk_mq_debugfs_rq_show(struct seq_file *m, struct request *rq)
 302 {
 303         const struct blk_mq_ops *const mq_ops = rq->q->mq_ops;
 304         const unsigned int op = rq->cmd_flags & REQ_OP_MASK;
 305
 306         seq_printf(m, "%p {.op=", rq);
 307         if (op < ARRAY_SIZE(op_name) && op_name[op])
 308                 seq_printf(m, "%s", op_name[op]);
 309         else
 310                 seq_printf(m, "%d", op);
 311         seq_puts(m, ", .cmd_flags=");
 312         blk_flags_show(m, rq->cmd_flags & ~REQ_OP_MASK, cmd_flag_name,
 313                        ARRAY_SIZE(cmd_flag_name));
 314         seq_puts(m, ", .rq_flags=");
 315         blk_flags_show(m, (__force unsigned int)rq->rq_flags, rqf_name,
 316                        ARRAY_SIZE(rqf_name));
 317         seq_puts(m, ", .atomic_flags=");
 318         blk_flags_show(m, rq->atomic_flags, rqaf_name, ARRAY_SIZE(rqaf_name));
 319         seq_printf(m, ", .tag=%d, .internal_tag=%d", rq->tag,
 320                    rq->internal_tag);
 321         if (mq_ops->show_rq)
 322                 mq_ops->show_rq(m, rq);
 323         seq_puts(m, "}\n");
 324         return 0;
 325 }
 326 EXPORT_SYMBOL_GPL(__blk_mq_debugfs_rq_show);
 327
 328 int blk_mq_debugfs_rq_show(struct seq_file *m, void *v)
 329 {
 330         return __blk_mq_debugfs_rq_show(m, list_entry_rq(v));
 331 }
 332 EXPORT_SYMBOL_GPL(blk_mq_debugfs_rq_show);
 333
 334 static void *queue_requeue_list_start(struct seq_file *m, loff_t *pos)
 335         __acquires(&q->requeue_lock)
 336 {
 337         struct request_queue *q = m->private;
 338
 339         spin_lock_irq(&q->requeue_lock);
 340         return seq_list_start(&q->requeue_list, *pos);
 341 }
 342
 343 static void *queue_requeue_list_next(struct seq_file *m, void *v, loff_t *pos)
 344 {
 345         struct request_queue *q = m->private;
 346
 347         return seq_list_next(v, &q->requeue_list, pos);
 348 }
 349
 350 static void queue_requeue_list_stop(struct seq_file *m, void *v)
 351         __releases(&q->requeue_lock)
 352 {
 353         struct request_queue *q = m->private;
 354
 355         spin_unlock_irq(&q->requeue_lock);
 356 }
 357
 358 static const struct seq_operations queue_requeue_list_seq_ops = {
 359         .start  = queue_requeue_list_start,
 360         .next   = queue_requeue_list_next,
 361         .stop   = queue_requeue_list_stop,
 362         .show   = blk_mq_debugfs_rq_show,
 363 };
 364
 365 static void *hctx_dispatch_start(struct seq_file *m, loff_t *pos)
 366         __acquires(&hctx->lock)
 367 {
 368         struct blk_mq_hw_ctx *hctx = m->private;
 369
 370         spin_lock(&hctx->lock);
 371         return seq_list_start(&hctx->dispatch, *pos);
 372 }
 373
 374 static void *hctx_dispatch_next(struct seq_file *m, void *v, loff_t *pos)
 375 {
 376         struct blk_mq_hw_ctx *hctx = m->private;
 377
 378         return seq_list_next(v, &hctx->dispatch, pos);
 379 }
 380
 381 static void hctx_dispatch_stop(struct seq_file *m, void *v)
 382         __releases(&hctx->lock)
 383 {
 384         struct blk_mq_hw_ctx *hctx = m->private;
 385
 386         spin_unlock(&hctx->lock);
 387 }
 388
 389 static const struct seq_operations hctx_dispatch_seq_ops = {
 390         .start  = hctx_dispatch_start,
 391         .next   = hctx_dispatch_next,
 392         .stop   = hctx_dispatch_stop,
 393         .show   = blk_mq_debugfs_rq_show,
 394 };
 395
 396 struct show_busy_params {
 397         struct seq_file         *m;
 398         struct blk_mq_hw_ctx    *hctx;
 399 };
 400
 401 /*
 402  * Note: the state of a request may change while this function is in progress,
 403  * e.g. due to a concurrent blk_mq_finish_request() call.
 404  */
 405 static void hctx_show_busy_rq(struct request *rq, void *data, bool reserved)
 406 {
 407         const struct show_busy_params *params = data;
 408
 409         if (blk_mq_map_queue(rq->q, rq->mq_ctx->cpu) == params->hctx &&
 410             blk_mq_rq_state(rq) != MQ_RQ_IDLE)
 411                 __blk_mq_debugfs_rq_show(params->m,
 412                                          list_entry_rq(&rq->queuelist));
 413 }
 414
 415 static int hctx_busy_show(void *data, struct seq_file *m)
 416 {
 417         struct blk_mq_hw_ctx *hctx = data;
 418         struct show_busy_params params = { .m = m, .hctx = hctx };
 419
 420         blk_mq_tagset_busy_iter(hctx->queue->tag_set, hctx_show_busy_rq,
 421                                 &params);
 422
 423         return 0;
 424 }
 425
 426 static int hctx_ctx_map_show(void *data, struct seq_file *m)
 427 {
 428         struct blk_mq_hw_ctx *hctx = data;
 429
 430         sbitmap_bitmap_show(&hctx->ctx_map, m);
 431         return 0;
 432 }
 433
 434 static void blk_mq_debugfs_tags_show(struct seq_file *m,
 435                                      struct blk_mq_tags *tags)
 436 {
 437         seq_printf(m, "nr_tags=%u\n", tags->nr_tags);
 438         seq_printf(m, "nr_reserved_tags=%u\n", tags->nr_reserved_tags);
 439         seq_printf(m, "active_queues=%d\n",
 440                    atomic_read(&tags->active_queues));
 441
 442         seq_puts(m, "\nbitmap_tags:\n");
 443         sbitmap_queue_show(&tags->bitmap_tags, m);
 444
 445         if (tags->nr_reserved_tags) {
 446                 seq_puts(m, "\nbreserved_tags:\n");
 447                 sbitmap_queue_show(&tags->breserved_tags, m);
 448         }
 449 }
 450
 451 static int hctx_tags_show(void *data, struct seq_file *m)
 452 {
 453         struct blk_mq_hw_ctx *hctx = data;
 454         struct request_queue *q = hctx->queue;
 455         int res;
 456
 457         res = mutex_lock_interruptible(&q->sysfs_lock);
 458         if (res)
 459                 goto out;
 460         if (hctx->tags)
 461                 blk_mq_debugfs_tags_show(m, hctx->tags);
 462         mutex_unlock(&q->sysfs_lock);
 463
 464 out:
 465         return res;
 466 }
 467
 468 static int hctx_tags_bitmap_show(void *data, struct seq_file *m)
 469 {
 470         struct blk_mq_hw_ctx *hctx = data;
 471         struct request_queue *q = hctx->queue;
 472         int res;
 473
 474         res = mutex_lock_interruptible(&q->sysfs_lock);
 475         if (res)
 476                 goto out;
 477         if (hctx->tags)
 478                 sbitmap_bitmap_show(&hctx->tags->bitmap_tags.sb, m);
 479         mutex_unlock(&q->sysfs_lock);
 480
 481 out:
 482         return res;
 483 }
 484
 485 static int hctx_sched_tags_show(void *data, struct seq_file *m)
 486 {
 487         struct blk_mq_hw_ctx *hctx = data;
 488         struct request_queue *q = hctx->queue;
 489         int res;
 490
 491         res = mutex_lock_interruptible(&q->sysfs_lock);
 492         if (res)
 493                 goto out;
 494         if (hctx->sched_tags)
 495                 blk_mq_debugfs_tags_show(m, hctx->sched_tags);
 496         mutex_unlock(&q->sysfs_lock);
 497
 498 out:
 499         return res;
 500 }
 501
 502 static int hctx_sched_tags_bitmap_show(void *data, struct seq_file *m)
 503 {
 504         struct blk_mq_hw_ctx *hctx = data;
 505         struct request_queue *q = hctx->queue;
 506         int res;
 507
 508         res = mutex_lock_interruptible(&q->sysfs_lock);
 509         if (res)
 510                 goto out;
 511         if (hctx->sched_tags)
 512                 sbitmap_bitmap_show(&hctx->sched_tags->bitmap_tags.sb, m);
 513         mutex_unlock(&q->sysfs_lock);
 514
 515 out:
 516         return res;
 517 }
 518
 519 static int hctx_io_poll_show(void *data, struct seq_file *m)
 520 {
 521         struct blk_mq_hw_ctx *hctx = data;
 522
 523         seq_printf(m, "considered=%lu\n", hctx->poll_considered);
 524         seq_printf(m, "invoked=%lu\n", hctx->poll_invoked);
 525         seq_printf(m, "success=%lu\n", hctx->poll_success);
 526         return 0;
 527 }
 528
 529 static ssize_t hctx_io_poll_write(void *data, const char __user *buf,
 530                                   size_t count, loff_t *ppos)
 531 {
 532         struct blk_mq_hw_ctx *hctx = data;
 533
 534         hctx->poll_considered = hctx->poll_invoked = hctx->poll_success = 0;
 535         return count;
 536 }
 537
 538 static int hctx_dispatched_show(void *data, struct seq_file *m)
 539 {
 540         struct blk_mq_hw_ctx *hctx = data;
 541         int i;
 542
 543         seq_printf(m, "%8u\t%lu\n", 0U, hctx->dispatched[0]);
 544
 545         for (i = 1; i < BLK_MQ_MAX_DISPATCH_ORDER - 1; i++) {
 546                 unsigned int d = 1U << (i - 1);
 547
 548                 seq_printf(m, "%8u\t%lu\n", d, hctx->dispatched[i]);
 549         }
 550
 551         seq_printf(m, "%8u+\t%lu\n", 1U << (i - 1), hctx->dispatched[i]);
 552         return 0;
 553 }
 554
 555 static ssize_t hctx_dispatched_write(void *data, const char __user *buf,
 556                                      size_t count, loff_t *ppos)
 557 {
 558         struct blk_mq_hw_ctx *hctx = data;
 559         int i;
 560
 561         for (i = 0; i < BLK_MQ_MAX_DISPATCH_ORDER; i++)
 562                 hctx->dispatched[i] = 0;
 563         return count;
 564 }
 565
 566 static int hctx_queued_show(void *data, struct seq_file *m)
 567 {
 568         struct blk_mq_hw_ctx *hctx = data;
 569
 570         seq_printf(m, "%lu\n", hctx->queued);
 571         return 0;
 572 }
 573
 574 static ssize_t hctx_queued_write(void *data, const char __user *buf,
 575                                  size_t count, loff_t *ppos)
 576 {
 577         struct blk_mq_hw_ctx *hctx = data;
 578
 579         hctx->queued = 0;
 580         return count;
 581 }
 582
 583 static int hctx_run_show(void *data, struct seq_file *m)
 584 {
 585         struct blk_mq_hw_ctx *hctx = data;
 586
 587         seq_printf(m, "%lu\n", hctx->run);
 588         return 0;
 589 }
 590
 591 static ssize_t hctx_run_write(void *data, const char __user *buf, size_t count,
 592                               loff_t *ppos)
 593 {
 594         struct blk_mq_hw_ctx *hctx = data;
 595
 596         hctx->run = 0;
 597         return count;
 598 }
 599
 600 static int hctx_active_show(void *data, struct seq_file *m)
 601 {
 602         struct blk_mq_hw_ctx *hctx = data;
 603
 604         seq_printf(m, "%d\n", atomic_read(&hctx->nr_active));
 605         return 0;
 606 }
 607
 608 static void *ctx_rq_list_start(struct seq_file *m, loff_t *pos)
 609         __acquires(&ctx->lock)
 610 {
 611         struct blk_mq_ctx *ctx = m->private;
 612
 613         spin_lock(&ctx->lock);
 614         return seq_list_start(&ctx->rq_list, *pos);
 615 }
 616
 617 static void *ctx_rq_list_next(struct seq_file *m, void *v, loff_t *pos)
 618 {
 619         struct blk_mq_ctx *ctx = m->private;
 620
 621         return seq_list_next(v, &ctx->rq_list, pos);
 622 }
 623
 624 static void ctx_rq_list_stop(struct seq_file *m, void *v)
 625         __releases(&ctx->lock)
 626 {
 627         struct blk_mq_ctx *ctx = m->private;
 628
 629         spin_unlock(&ctx->lock);
 630 }
 631
 632 static const struct seq_operations ctx_rq_list_seq_ops = {
 633         .start  = ctx_rq_list_start,
 634         .next   = ctx_rq_list_next,
 635         .stop   = ctx_rq_list_stop,
 636         .show   = blk_mq_debugfs_rq_show,
 637 };
 638 static int ctx_dispatched_show(void *data, struct seq_file *m)
 639 {
 640         struct blk_mq_ctx *ctx = data;
 641
 642         seq_printf(m, "%lu %lu\n", ctx->rq_dispatched[1], ctx->rq_dispatched[0]);
 643         return 0;
 644 }
 645
 646 static ssize_t ctx_dispatched_write(void *data, const char __user *buf,
 647                                     size_t count, loff_t *ppos)
 648 {
 649         struct blk_mq_ctx *ctx = data;
 650
 651         ctx->rq_dispatched[0] = ctx->rq_dispatched[1] = 0;
 652         return count;
 653 }
 654
 655 static int ctx_merged_show(void *data, struct seq_file *m)
 656 {
 657         struct blk_mq_ctx *ctx = data;
 658
 659         seq_printf(m, "%lu\n", ctx->rq_merged);
 660         return 0;
 661 }
 662
 663 static ssize_t ctx_merged_write(void *data, const char __user *buf,
 664                                 size_t count, loff_t *ppos)
 665 {
 666         struct blk_mq_ctx *ctx = data;
 667
 668         ctx->rq_merged = 0;
 669         return count;
 670 }
 671
 672 static int ctx_completed_show(void *data, struct seq_file *m)
 673 {
 674         struct blk_mq_ctx *ctx = data;
 675
 676         seq_printf(m, "%lu %lu\n", ctx->rq_completed[1], ctx->rq_completed[0]);
 677         return 0;
 678 }
 679
 680 static ssize_t ctx_completed_write(void *data, const char __user *buf,
 681                                    size_t count, loff_t *ppos)
 682 {
 683         struct blk_mq_ctx *ctx = data;
 684
 685         ctx->rq_completed[0] = ctx->rq_completed[1] = 0;
 686         return count;
 687 }
 688
 689 static int blk_mq_debugfs_show(struct seq_file *m, void *v)
 690 {
 691         const struct blk_mq_debugfs_attr *attr = m->private;
 692         void *data = d_inode(m->file->f_path.dentry->d_parent)->i_private;
 693
 694         return attr->show(data, m);
 695 }
 696
 697 static ssize_t blk_mq_debugfs_write(struct file *file, const char __user *buf,
 698                                     size_t count, loff_t *ppos)
 699 {
 700         struct seq_file *m = file->private_data;
 701         const struct blk_mq_debugfs_attr *attr = m->private;
 702         void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
 703
 704         if (!attr->write)
 705                 return -EPERM;
 706
 707         return attr->write(data, buf, count, ppos);
 708 }
 709
 710 static int blk_mq_debugfs_open(struct inode *inode, struct file *file)
 711 {
 712         const struct blk_mq_debugfs_attr *attr = inode->i_private;
 713         void *data = d_inode(file->f_path.dentry->d_parent)->i_private;
 714         struct seq_file *m;
 715         int ret;
 716
 717         if (attr->seq_ops) {
 718                 ret = seq_open(file, attr->seq_ops);
 719                 if (!ret) {
 720                         m = file->private_data;
 721                         m->private = data;
 722                 }
 723                 return ret;
 724         }
 725
 726         if (WARN_ON_ONCE(!attr->show))
 727                 return -EPERM;
 728
 729         return single_open(file, blk_mq_debugfs_show, inode->i_private);
 730 }
 731
 732 static int blk_mq_debugfs_release(struct inode *inode, struct file *file)
 733 {
 734         const struct blk_mq_debugfs_attr *attr = inode->i_private;
 735
 736         if (attr->show)
 737                 return single_release(inode, file);
 738         else
 739                 return seq_release(inode, file);
 740 }
 741
 742 static const struct file_operations blk_mq_debugfs_fops = {
 743         .open           = blk_mq_debugfs_open,
 744         .read           = seq_read,
 745         .write          = blk_mq_debugfs_write,
 746         .llseek         = seq_lseek,
 747         .release        = blk_mq_debugfs_release,
 748 };
 749
 750 static const struct blk_mq_debugfs_attr blk_mq_debugfs_queue_attrs[] = {
 751         {"poll_stat", 0400, queue_poll_stat_show},
 752         {"requeue_list", 0400, .seq_ops = &queue_requeue_list_seq_ops},
 753         {"state", 0600, queue_state_show, queue_state_write},
 754         {"write_hints", 0600, queue_write_hint_show, queue_write_hint_store},
 755         {},
 756 };
 757
 758 static const struct blk_mq_debugfs_attr blk_mq_debugfs_hctx_attrs[] = {
 759         {"state", 0400, hctx_state_show},
 760         {"flags", 0400, hctx_flags_show},
 761         {"dispatch", 0400, .seq_ops = &hctx_dispatch_seq_ops},
 762         {"busy", 0400, hctx_busy_show},
 763         {"ctx_map", 0400, hctx_ctx_map_show},
 764         {"tags", 0400, hctx_tags_show},
 765         {"tags_bitmap", 0400, hctx_tags_bitmap_show},
 766         {"sched_tags", 0400, hctx_sched_tags_show},
 767         {"sched_tags_bitmap", 0400, hctx_sched_tags_bitmap_show},
 768         {"io_poll", 0600, hctx_io_poll_show, hctx_io_poll_write},
 769         {"dispatched", 0600, hctx_dispatched_show, hctx_dispatched_write},
 770         {"queued", 0600, hctx_queued_show, hctx_queued_write},
 771         {"run", 0600, hctx_run_show, hctx_run_write},
 772         {"active", 0400, hctx_active_show},
 773         {},
 774 };
 775
 776 static const struct blk_mq_debugfs_attr blk_mq_debugfs_ctx_attrs[] = {
 777         {"rq_list", 0400, .seq_ops = &ctx_rq_list_seq_ops},
 778         {"dispatched", 0600, ctx_dispatched_show, ctx_dispatched_write},
 779         {"merged", 0600, ctx_merged_show, ctx_merged_write},
 780         {"completed", 0600, ctx_completed_show, ctx_completed_write},
 781         {},
 782 };
 783
 784 static bool debugfs_create_files(struct dentry *parent, void *data,
 785                                  const struct blk_mq_debugfs_attr *attr)
 786 {
 787         d_inode(parent)->i_private = data;
 788
 789         for (; attr->name; attr++) {
 790                 if (!debugfs_create_file(attr->name, attr->mode, parent,
 791                                          (void *)attr, &blk_mq_debugfs_fops))
 792                         return false;
 793         }
 794         return true;
 795 }
 796
 797 int blk_mq_debugfs_register(struct request_queue *q)
 798 {
 799         struct blk_mq_hw_ctx *hctx;
 800         int i;
 801
 802         if (!blk_debugfs_root)
 803                 return -ENOENT;
 804
 805         q->debugfs_dir = debugfs_create_dir(kobject_name(q->kobj.parent),
 806                                             blk_debugfs_root);
 807         if (!q->debugfs_dir)
 808                 return -ENOMEM;
 809
 810         if (!debugfs_create_files(q->debugfs_dir, q,
 811                                   blk_mq_debugfs_queue_attrs))
 812                 goto err;
 813
 814         /*
 815          * blk_mq_init_sched() attempted to do this already, but q->debugfs_dir
 816          * didn't exist yet (because we don't know what to name the directory
 817          * until the queue is registered to a gendisk).
 818          */
 819         if (q->elevator && !q->sched_debugfs_dir)
 820                 blk_mq_debugfs_register_sched(q);
 821
 822         /* Similarly, blk_mq_init_hctx() couldn't do this previously. */
 823         queue_for_each_hw_ctx(q, hctx, i) {
 824                 if (!hctx->debugfs_dir && blk_mq_debugfs_register_hctx(q, hctx))
 825                         goto err;
 826                 if (q->elevator && !hctx->sched_debugfs_dir &&
 827                     blk_mq_debugfs_register_sched_hctx(q, hctx))
 828                         goto err;
 829         }
 830
 831         return 0;
 832
 833 err:
 834         blk_mq_debugfs_unregister(q);
 835         return -ENOMEM;
 836 }
 837
 838 void blk_mq_debugfs_unregister(struct request_queue *q)
 839 {
 840         debugfs_remove_recursive(q->debugfs_dir);
 841         q->sched_debugfs_dir = NULL;
 842         q->debugfs_dir = NULL;
 843 }
 844
 845 static int blk_mq_debugfs_register_ctx(struct blk_mq_hw_ctx *hctx,
 846                                        struct blk_mq_ctx *ctx)
 847 {
 848         struct dentry *ctx_dir;
 849         char name[20];
 850
 851         snprintf(name, sizeof(name), "cpu%u", ctx->cpu);
 852         ctx_dir = debugfs_create_dir(name, hctx->debugfs_dir);
 853         if (!ctx_dir)
 854                 return -ENOMEM;
 855
 856         if (!debugfs_create_files(ctx_dir, ctx, blk_mq_debugfs_ctx_attrs))
 857                 return -ENOMEM;
 858
 859         return 0;
 860 }
 861
 862 int blk_mq_debugfs_register_hctx(struct request_queue *q,
 863                                  struct blk_mq_hw_ctx *hctx)
 864 {
 865         struct blk_mq_ctx *ctx;
 866         char name[20];
 867         int i;
 868
 869         if (!q->debugfs_dir)
 870                 return -ENOENT;
 871
 872         snprintf(name, sizeof(name), "hctx%u", hctx->queue_num);
 873         hctx->debugfs_dir = debugfs_create_dir(name, q->debugfs_dir);
 874         if (!hctx->debugfs_dir)
 875                 return -ENOMEM;
 876
 877         if (!debugfs_create_files(hctx->debugfs_dir, hctx,
 878                                   blk_mq_debugfs_hctx_attrs))
 879                 goto err;
 880
 881         hctx_for_each_ctx(hctx, ctx, i) {
 882                 if (blk_mq_debugfs_register_ctx(hctx, ctx))
 883                         goto err;
 884         }
 885
 886         return 0;
 887
 888 err:
 889         blk_mq_debugfs_unregister_hctx(hctx);
 890         return -ENOMEM;
 891 }
 892
 893 void blk_mq_debugfs_unregister_hctx(struct blk_mq_hw_ctx *hctx)
 894 {
 895         debugfs_remove_recursive(hctx->debugfs_dir);
 896         hctx->sched_debugfs_dir = NULL;
 897         hctx->debugfs_dir = NULL;
 898 }
 899
 900 int blk_mq_debugfs_register_hctxs(struct request_queue *q)
 901 {
 902         struct blk_mq_hw_ctx *hctx;
 903         int i;
 904
 905         queue_for_each_hw_ctx(q, hctx, i) {
 906                 if (blk_mq_debugfs_register_hctx(q, hctx))
 907                         return -ENOMEM;
 908         }
 909
 910         return 0;
 911 }
 912
 913 void blk_mq_debugfs_unregister_hctxs(struct request_queue *q)
 914 {
 915         struct blk_mq_hw_ctx *hctx;
 916         int i;
 917
 918         queue_for_each_hw_ctx(q, hctx, i)
 919                 blk_mq_debugfs_unregister_hctx(hctx);
 920 }
 921
 922 int blk_mq_debugfs_register_sched(struct request_queue *q)
 923 {
 924         struct elevator_type *e = q->elevator->type;
 925
 926         if (!q->debugfs_dir)
 927                 return -ENOENT;
 928
 929         if (!e->queue_debugfs_attrs)
 930                 return 0;
 931
 932         q->sched_debugfs_dir = debugfs_create_dir("sched", q->debugfs_dir);
 933         if (!q->sched_debugfs_dir)
 934                 return -ENOMEM;
 935
 936         if (!debugfs_create_files(q->sched_debugfs_dir, q,
 937                                   e->queue_debugfs_attrs))
 938                 goto err;
 939
 940         return 0;
 941
 942 err:
 943         blk_mq_debugfs_unregister_sched(q);
 944         return -ENOMEM;
 945 }
 946
 947 void blk_mq_debugfs_unregister_sched(struct request_queue *q)
 948 {
 949         debugfs_remove_recursive(q->sched_debugfs_dir);
 950         q->sched_debugfs_dir = NULL;
 951 }
 952
 953 int blk_mq_debugfs_register_sched_hctx(struct request_queue *q,
 954                                        struct blk_mq_hw_ctx *hctx)
 955 {
 956         struct elevator_type *e = q->elevator->type;
 957
 958         if (!hctx->debugfs_dir)
 959                 return -ENOENT;
 960
 961         if (!e->hctx_debugfs_attrs)
 962                 return 0;
 963
 964         hctx->sched_debugfs_dir = debugfs_create_dir("sched",
 965                                                      hctx->debugfs_dir);
 966         if (!hctx->sched_debugfs_dir)
 967                 return -ENOMEM;
 968
 969         if (!debugfs_create_files(hctx->sched_debugfs_dir, hctx,
 970                                   e->hctx_debugfs_attrs))
 971                 return -ENOMEM;
 972
 973         return 0;
 974 }
 975
 976 void blk_mq_debugfs_unregister_sched_hctx(struct blk_mq_hw_ctx *hctx)
 977 {
 978         debugfs_remove_recursive(hctx->sched_debugfs_dir);
 979         hctx->sched_debugfs_dir = NULL;
 980 }